Joined: Nov 2006
Posts: 19,810
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From: NJ, NYC, LI
Bikes: 1940s Fothergill, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1974 Fuji "the Ace", 1976 Holdsworth 650b conversion rando bike, 1983 Trek 720 tourer, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...
3-armed cranks should be divided up according to the bolt circle size. The largest group is probably the 116 mm family, which includes cottered steel cranks from Stronglight, Nervar, Magistroni, Williams (though only the 1200 model), and many more; and chain rings from Simplex etc; followed by cotterless ones from Stronglight, Nervar, TA, Campagnolo. I don't know why these disappeared, but I'm suspicious it was simply a matter of an industry not seeing the profit in retrocompatibility.
Most Williams and Nicklin 3-armed cottered cranks were a smaller bolt circle that never made the jump to cotterless or aluminum.
There have been several other 3-arm cranks with other bolt circle diameters, including Rene Herse, SR, Shimano; and they have no cross-compatibility, which means they disappear as soon as they are no longer made.
SR Custom-3 is an interesting exception with its 86 mm bcd, since FSA has recently started making compatible cranks, and rings. I like them.
Last edited by rhm; 01-14-17 at 02:06 AM.